Drum Positioning System

ABSTRACT

Various embodiments and methods relating to adjusting and maintaining a relative positioning and/or pressure between a first drum and a second drum are disclosed.

This application claims the benefit of U.S. provisional patentapplication Ser. No. 60/985,975, filed on Nov. 6, 2007, entitled “DRUMPOSITIONING SYSTEM”.

BACKGROUND

Pairs of drums are sometimes used to transfer material or to interactwith material between such drums. Such drums sometimes include run outor other dimensional inconsistencies. These dimensional inconsistenciesmay cause inconsistent relative positioning and compressive pressuresbetween the drums.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of an apparatus including apositioning system according to an example embodiment.

FIG. 2 is a schematic illustration of another embodiment of theapparatus of FIG. 1 including another embodiment of the positioningsystem according to an example embodiment.

FIG. 3 is a schematic illustration of another embodiment of theapparatus of FIG. 1 including another embodiment of the positioningsystem according to an example embodiment.

FIG. 4 is a schematic illustration of another embodiment of theapparatus of FIG. 1 including another embodiment of the positioningsystem according to an example embodiment.

FIG. 5 is an end elevational view of another embodiment of the apparatusof FIG. 1 including another embodiment of the positioning systemaccording to an example embodiment.

FIG. 6 is a slight elevational view of the apparatus and the positioningsystem of FIG. 5 according to an example embodiment.

FIG. 7 is an end elevational view of the apparatus of FIG. 5illustrating the positioning system in a first position according to anexample embodiment.

FIG. 8 is an end elevational view of the apparatus of FIG. 5illustrating the positioning system in a second position according to anexample embodiment.

FIG. 9 is a schematically station of a printer including the positioningsystem of FIGS. 5 and 6 according to an example embodiment.

DETAILED DESCRIPTION OF THE EXAMPLE EMBODIMENTS

FIG. 1 schematically illustrates an apparatus 20 including a positioningsystem 22 and drums 24, 26 according to an example embodiment. Drums 24,26 are configured to either transfer material from one drum to anotherdrum or to interact with a material or medium passing therebetween. Aswill be described hereafter, positioning system 22 facilitatesadjustment and control of the relative positioning and compressivepressure between drums 24 and 26.

In addition to drums 24, 26 and positioning system 22, apparatus 20further includes support 28, drum drive 30, support 32, bias 34, drumdrive 36, input 38, sensor 40 and Controller 42. As shown by FIG. 1,drums 24, 26 comprise cylinders rotationally supported opposite to oneanother. In the example illustrated, drum 24 is rotationally supportedabout a fixed or stationary axis 46. Drum 26 is rotationally supportedabout a movable axis 48. In the example illustrated, drum 24 includes anouter surface 50 that is generally circumferential or round except forone or more non-round outer surface portions 52. Non-round outer surfaceportion 50 to comprises a notch, opening or recess along surface 50. Inother embodiment, portion 52 may comprise a flat or may comprise aprojection or protuberance. Similar to drum 24, drum 26 has an outersurface 54 that is substantially circumferential or round except for oneor more non-round outer surface portions 56. In the example illustrated,portions 56 comprise a flat. In other embodiments, drums 54 may omitnon-round outer surface portions or may include additional oralternative non-round outer surface portions.

Support 28 (schematically illustrated) comprises a substantiallystationary structure rotationally supporting drum 50 about axis 46. Drumdrive 30 comprises a mechanism configured to rotationally drive drum 24about axis 46. In the example illustrated, drum drive 30 comprises astep or motor facilitating controlled rotation of drum 24. In otherembodiments, drum drive 30 may comprise other forms of motors orrotational actuators. In yet other embodiments where drum 24 freelyrotates, drum drive 30 may be omitted.

Support 30 comprises a structure configured to movably support axis 48and drum 26 relative to axis 46 and drum 24. In the particular exampleillustrated, support 30 to comprises an extension or arm having a firstend 60 rotationally supporting drum 26 and a second end or portion 62rotationally or pivotally connected to another support 64 about axis 66.Support 64 (schematically shown) comprises a stationary or fixedstructure thoroughly supporting arm 32 and drum 26. In otherembodiments, drum 26 and its rotational axis 48 may be movably supportedrelative to drum 24 in other fashions. For example, in blue of beingpivotable he supported, drum 26 may alternatively be configured totranslate or slide towards and away from drum 24.

Bias 34 comprises a mechanism coupled between arm 32 and support 68 andconfigured to resiliently urge arm 32 in a clock-wise direction aboutaxis 66 (as seen in FIG. 1) so as to also urge drum 26 towards drum 24.Bias 34 assists in maintaining positioning of drum 26 relative to drum24 despite vibration or shock. In one embodiment, apparatus 20 includesa pair of such biases 24 located proximate to opposite axial ends ofdrum 26. Support 68 comprises any stationary fixed structure and may bepart of support 46 or support 64.

In the example illustrated, bias 34 comprises a tension spring connectedbetween arm 32 and support 68. In other embodiment, bias 34 may comprisea compression spring coupled between arm 32 and a support (not shown) onan opposite side of axis 66. In still other embodiment, bias 34 maycomprise a torsion spring connected between support 64 and arm 32 aboutaxis 66. In some embodiments, bias 34 may be omitted such as wheregravity is employed to urge drum 26 towards drum 24.

Drum drive 36 comprises a source of torque operably coupled to drum 26so as to rotationally drive drum 26 about axis 48. In the exampleillustrated, drum drive 36 comprises a motor. In one embodiment, drumdrive 36 comprises a stepper motor, providing precise control overrotational positioning of drum 26. In other embodiments, drum drive 36may comprise other sources of torque. In some embodiment, drum drive 36may be omitted.

Positioning system 22 comprises a system or arrangement of componentsrestructures configured to adjust relative positioning and pressurebetween drum 24 and drum 26 and to maintain a selected relativepositioning and pressure despite run out or other dimensionalinconsistencies of drums 24, 26. Positioning system 22 includes bearer74, bearer 76 and spacer mechanism 78.

Bearer 74 comprises a cylindrical member, projection, hub or otherstructure coupled to drum 24 so as to rotate with drum 24 about axis 46.For purposes of this disclosure, the term “coupled” shall mean thejoining of two members directly or indirectly to one another. Suchjoining may be stationary in nature or movable in nature. Such joiningmay be achieved with the two members or the two members and anyadditional intermediate members being integrally formed as a singleunitary body with one another or with the two members or the two membersand any additional intermediate member being attached to one another.Such joining may be permanent in nature or alternatively may beremovable or releasable in nature. The term “operably coupled” shallmean that two members are directly or indirectly joined such that motionmay be transmitted from one member to the other member directly or viaintermediate members. Bearer 74 includes an outer circumferentialsurface 80 configured to bear against, abut, contact or engage portionsof spacer mechanism 78.

Bearer 76 is similar to bearer 74. Bearer 76 comprises a cylindricalmember, projection, hub or other structure coupled to drum 26 so as torotate with drum 26 about axis 48. Bearer 76 comprises a cylindricalmember, projection, hub or other structure coupled to drum 26 so as torotate with drum 26 about axis 46. Bearer 76 includes an outercircumferential surface 82 configured to bear against, about, contact orengage portions of spacer mechanism 78. Although bearers 74, 76 areillustrated as having substantially the same diameter, in otherembodiments, bearers 74, 76 may have different diameters.

Spacer mechanism 78 comprises one or more components between bearers 74and 76 in mutual engagement with surfaces 80 and 82 that continuouslyextend across the gap or space between opposed portion of surfaces 80and 82 so as to space bearers 74 and 76 from one another. As a result,spacer mechanism 78 also controls either the space S between the outersurfaces 50 and 54 of drums 24 and 26, respectively, or the amount ofpressure exerted by drum 54 upon drum 52 (and any intermediatestructure, media or material) or vice versa. Spacer mechanism 78maintains a selected spacing or distance between bearers 74, 76 tomaintain a desire space air pressure between drums 24, 26. In addition,spacer mechanism 78 is configured to be adjusted or actuated betweendifferent states in which opposed portions of surfaces 80 and 82 ofbearers 74 and 76 are differently spaced from one another. As a result,spacer mechanism 78 may be adjusted to select a desired spacing or adesired compressive pressure between drums 24 and 26.

For example, in one embodiment, spacer mechanism 78 may be actuated to afirst state in which bearers 74 and 76 are spaced such that opposedportions of surfaces 50 and 54 are also spaced by a first distancegreater than zero. In another embodiment, spacer mechanism 78 may beactuated to a second state in which bearers 74 and 76 are spaced suchthat opposed portions of surfaces 50 and 54 are also spaced by seconddistance greater than zero and different than the first distance. Inanother embodiment, spacer mechanism 78 may be actuated to a third statein which bearers 74 and 76 are spaced such that opposed portions ofsurfaces 50 and 54 are in contact with one another with a first pressurebeing applied across surfaces. In another embodiment, spacer mechanism78 may be actuated to a second state in which bearers 74 and 76 arespaced such that opposed portions of surfaces 50 and 54 are in contactwith one another or are in contact with an intermediate structure ormedium, wherein a second compressive pressure, different than the firstpressure, is applied across such surfaces or across the intermediatestructure or medium.

According to one embodiment, positioning system 22 includes an identicalset of bearers 74, 76 and an identical spacer mechanism 78 on anopposite axial end of drums 24, 26. In one embodiment, spacer mechanism78 on opposite axial ends of drums 24, 26 are independently adjustableor actuatable so as to provide distinct spaces between the pairs ofbearers 74, 76 on the opposite axial ends. As a result, differentspacings or different pressures may be provided at different locationsalong the axis of drum 24 or drum 26. In other embodiments, the oppositespacer mechanisms 78 may actuate together in substantial unison. Instill other embodiments, positioning system 22 may include a single setof bearers 74, 76 and a single spacer mechanism 78.

Input 38 comprises one or more devices configured to facilitate enteringof commands or instructions to controller 42 by a person or operator.Input 38 facilitates entry of commands directing controller 42 togenerate control signals actuating the one or more spacer mechanism 78to selected states such provide a desired spacing and/or pressurebetween drums 24, 26. Examples of input 38 include, but are not limitedto, a keyboard, a keypad, a touchscreen, a touchpad, one or moreswitches, a one or more slider bars, a mouse, a stylus, and a microphonewith associated speech recognition hardware or software. Input 38 mayalso comprise an external communication port for receiving commands froman external device that is across a network, the internet or othercommunication mediums. Some embodiment come in to 38 may be omitted.

Sensor 40 comprises one or more sensing devices located and configuredto sense or detect a spacing between surfaces 80, 82, a spacing betweensurfaces 50, 54 or a pressure being applied or occurring betweensurfaces 50, 52. Sensor 40 provides feedback to controller 42, enablingcontroller 42 to adjust the settings of spacer mechanism 78 to achieve adesired spacing or pressure result. In other embodiments, sensor 40 maybe omitted.

Controller 42 comprises one or more processors or processing unitsconfigured to generate control signals which cause spacer mechanism 78to be actuated between different states in which spacer mechanism 78spaces bearers 74, 76 by different distances. In the exampleillustrated, controller 42 is further configured to receive and analyzefeedback from sensors 40 and two adjusts spacer mechanism 78 to achievea desired spacing or pressure. In the example illustrated, controller 42is also configured to adjust the relative positioning or pressurebetween drums 24 and 26 based upon command instructions received viainput 38.

For purposes of this application, the term “processing unit” shall meana presently developed or future developed processing unit that executessequences of instructions contained in a memory. Execution of thesequences of instructions causes the processing unit to perform stepssuch as generating control signals. The instructions may be loaded in arandom access memory (RAM) for execution by the processing unit from aread only memory (ROM), a mass storage device, or some other persistentstorage. In other embodiments, hard wired circuitry may be used in placeof or in combination with software instructions to implement thefunctions described. For example, controller 92 may be embodied as partof one or more application-specific integrated circuits (ASICs). Unlessotherwise specifically noted, the controller is not limited to anyspecific combination of hardware circuitry and software, nor to anyparticular source for the instructions executed by the processing unit.In addition to generating control signals actuating spacer mechanism 78,controller 42 they also generate control signals directing from drives30 and 36 to rotational a drive to drums 24 and 26, respectively.Controller 42 may also generate control signals directing otheroperations of apparatus 20.

Overall, positioning system 22 facilitates constant contact betweenbearers 74, 76 for shockless rotation of drums 24 and 26. Positioningsystem 22 permits the spacing or pressure between surfaces 1554 of drums24 and 26, respectively, to be rapidly adjusted. Spacer mechanism 78facilitates automatic adjustment in response to control signals fromcontroller 42 based upon instructions contained within an associatedmemory, commands received via input 38 are feedback received via sensor40. In particular embodiments, the spacing or pressure at opposite axialends of drums 24 and 26 may be independently adjusted. At the same time,the pressure or spacing may be maintained despite run out or dimensionalinconsistencies in one or both of drums 24, 26.

FIG. 2 schematically illustrates apparatus 120, another embodiment ofapparatus 20. Apparatus 120 is similar to apparatus 20 except thatapparatus 120 includes positioning system 122 instead of positioningsystem 22. Those remaining structures or components of system 120 whichcorrespond to structures or components of system 20 are numberedsimilarly.

Positioning system 122 includes bearers 74, 76, as generally describedabove with respect to FIG. 1, and a pair of spacer mechanisms 178 (oneof which is shown) which are located at opposite axial ends of drums 24,26. Spacer mechanism 178 adjusts and maintains the spacing betweensurfaces 80 and 82 of bearers 74 and 76, respectively. Spacer mechanism178 includes spacer 181 and actuation system 193. The spacer 181comprises one or more structures continuously extending between surfaces80 and 82 of bearers 74 and 76, respectively, that are configured tohave a changing dimension between surfaces 80 and 82 in response tobeing moved relative to surfaces 80 and 82 while remaining in contactwith surfaces 80 and 82. In the example illustrated, spacer 181comprises a wedge extending between and mutually engaging surfaces 80and 82. Movement of wedge 181 in either direction as indicated by arrows194 changes the spacing between surfaces 80 and 82 and also changes thespacing between surfaces 50 and 54 of drums 24 and 26 or the pressurebetween surfaces 50 and 54 of drums 24 and 26, respectively. In theexample illustrated, movement of spacer 181 to the left (as seen in FIG.2) moves bearer 76 and its associated drum 26 against the bias providedby bias 34 away from bearers 74 and drum 24, increasing the gap orspacing between drums 24, 26 or decreasing the compressive force orpressure therebetween. Alternatively, movement of spacer 181 to theright (as seen in FIG. 2) permits bearer 76 and its associated drum 26to move with the assistance of the bias provided by bias 34 towardsbearers 74 and drum 24, decreasing the gap or spacing between drums 24,26 or increasing the compressive force or pressure therebetween.

In one embodiment, the wedge of spacer 181 may include low frictionsurfaces in contact with surfaces 80 and 82 of bearers 74 and 76,respectively. For example, such surfaces may be formed frompolytetrafluoroethylene. In another embodiment, such surfaces may beprovided with rollers, ball bearings or other bearing mechanisms.Although the shape of spacer 181 is illustrated as a right triangle, inother embodiments, spacer 181 may have other shapes and configurations.Spacer 181 may have other configurations other than a wedge or triangleas well.

Actuation system 193 comprises a device configured to selectively movespacer 181 to the left or to the right so as to adjust spacing ofbearers 74 and 76. In one embodiment, actuation system 193 may comprisea rack and pinion/worm gear arrangement powered by a motor, such as atwo directional motor or a stepper motor, configured to linearlytranslate spacer 181. In another embodiment, actuation system 193 maycomprise a hydraulic or pneumatic cylinder-piston assembly or anelectric solenoid. In yet another embodiment, actuation system 193 maycomprise one or more motor driven cams which facilitate translation ofspacer 181 in either of the directions indicated by arrows 194. As shownby FIG. 2, actuator 183 translates or moves spacer 181 in response tocontrol signals received from controller 42.

FIG. 3 schematically illustrates apparatus 220, another embodiment ofapparatus 20 shown in FIG. 1. Apparatus 220 is similar to apparatus 20except that apparatus 220 includes positioning system 222 instead ofpositioning system 22. Those remaining structures or components ofsystem 220 which correspond to structures or components of system 20 arenumbered similarly.

Positioning system 222 includes bearers 74, 76, as generally describedabove with respect to FIG. 1, and a pair of spaced spacer mechanisms 278(one of which is shown) which are located at opposite axial ends ofdrums 24, 26. Spacer mechanism 278 adjusts and maintains the spacingbetween surfaces 80 and 82 of bearers 74 and 76, respectively. Spacermechanism 278 includes spacers 281, 283, 285 and actuation system 293.Spacer 281 comprises a roller having an outer circumferential surface295 in mutual contact with surface 80 of bearer 74 and spacer 285.Spacer 281 rotates about a generally fixed or stationary axis 297.

Spacer 283 comprises a roller having an outer circumferential surface299 in mutual contact with surface 82 of bearer 76 and spacer 285.Spacer 283 rotates about an axis 301 that is movably supported betweenbearer 76 and bearer 74. For example, in one embodiment, spacer 283 mayrotate about an axis 301 that is provided by a shaft that is permittedto rotate and slide or move vertically with a substantially verticalchannel or slot provided by a support structure or frame structure, suchas support 68. As a result, bias 34 urges error 76 against spacer 283which is moved so as to abut and bear against spacer 285.

Spacer 285 comprises a roller having an outer circumferential surface303 in mutual contact with surface 299 of spacer 283 and surface 295 ofspacer 281. In the example illustrated, spacer 303 is rotationallysupported about axis 305. In other embodiments, spacer 285 may comprisea cylinder having a low friction out of circumferential surface, thecylinder being fixed against rotation.

Actuation system 293 comprising mechanism operably coupled to spacer 285sets to selectively move spacer 285 in either of the directionsindicated by arrows 307 relative to spacers 281 and 283. Such movementof spacer 285 adjusts the spacing between spacers 281 and 283. As aresult, such movement of spacer 285 further adjusts the spacing betweenbearers 74 and 76 to cause adjustment of the relative positioning orcompression pressures between drums 24 and 26.

According to one embodiment, actuation system 293 may comprise a rackand pinion arrangement powered by a motor, such as a two directionalmotor or a stepper motor, configured to linearly translate spacer 285.In another embodiment, actuation system 293 may comprise a hydraulic orpneumatic cylinder-piston assembly or an electric solenoid. In yetanother embodiment, actuation system 293 may comprise one or more motordriven cams which facilitate translation of spacer 285 in either of thedirections indicated by arrows 307. As shown by FIG. 3, actuation system293 translates or moves spacer 285 in response to control signalsreceived from controller 42.

FIG. 4 schematically illustrates apparatus 320, another embodiment ofapparatus 20 shown in FIG. 1. Apparatus 320 is similar to apparatus 20except that apparatus 320 includes positioning system 322 instead ofpositioning system 22. Those remaining structures or components ofsystem 320 which correspond to structures or components of system 20 arenumbered similarly.

Positioning system 322 includes bearers 74, 76, as generally describedabove with respect to FIG. 1, and a pair of spaced spacer mechanisms 378(one of which is shown) which are located at opposite axial ends ofdrums 24, 26. Spacer mechanism 378 adjusts and maintains the spacingbetween surfaces 80 and 82 of bearers 74 and 76, respectively. Spacermechanism 378 includes spacers 381, 385 and actuation system 393. Spacer381 comprises a roller having an outer circumferential surface 395 inmutual contact with surface 80 of bearer 74 and spacer 285. Spacer 381rotates about a generally fixed or stationary axis 397.

Spacer 385 comprises a roller having an outer circumferential surface403 in mutual contact with surface 82 of spacer 76 and surface 395 ofspacer 381. In the example illustrated, spacer 303 is rotationallysupported about axis 405. In other embodiments, spacer 385 may comprisea cylinder having a low friction outer circumferential surface, thecylinder being fixed against rotation.

Actuation system 393 comprising mechanism operably coupled to spacer 385sets to selectively move spacer 385 in either of the directionsindicated by arrows 407 relative to bearer 76 and spacer 381. Suchmovement of spacer 385 adjusts the spacing between spacers 381 andbearer 76. As a result, such movement of spacer 385 further adjusts thespacing between bearers 74 and 76 to cause adjustment of the relativepositioning or compression pressures between drums 24 and 26.

According to one embodiment, actuation system 393 may comprise a rackand pinion arrangement powered by a motor, such as a two directionalmotor or a stepper motor, configured to linearly translate spacer 385.In another embodiment, actuation system 393 may comprise a hydraulic orpneumatic cylinder-piston assembly or an electric solenoid. In yetanother embodiment, actuation system 393 may comprise one or more motordriven cams which facilitate translation of spacer 385 in either of thedirections indicated by arrows 407. As shown by FIG. 4, actuation system393 translates or moves spacer 385 in response to control signalsreceived from controller 42.

FIGS. 5-8 illustrate apparatus 420, another embodiment of apparatus 20(shown in FIG. 1). As shown by FIGS. 5 and 6, apparatus 420 includespositioning systems 422, a particular embodiment of positioning system22 (shown in FIG. 1). In addition, apparatus or 420 also includes drums24, 26 (described above with respect to apparatus 20), supports 428A,428B (collectively referred to as supports 428), drum drive 30 (shownand described above with respect to FIG. 1), arms 432A, 432B(collectively referred to as arms 432), biases 434A, 434B (collectivelyreferred to as biases 434), drum drive 36 (shown and described abovewith respect to FIG. 1), input 38 (shown and described above withrespect to FIG. 1), sensor 40 (shown and described above with respect toFIG. 1) and controller 42 (described above with respect to FIG. 1).

Supports 428 comprise a pair of substantially stationary structures atopposite ends of drums 24, 26. Supports 428 rotationally support drum 24about axis 46. Arms 432 comprise structures at opposite ends of drum 26that are configured to movably support axis 48 and drum 26 relative toaxis 46 and drum 24. In the particular example illustrated, each of arms432 comprises an extension having a first central portion 460 (shown inFIG. 5) rotationally supporting drum 26, a first end or portion 462(shown in FIG. 5) rotationally or pivotally connected to an associatedsupport 428A or 428B about axis 466, and a second end or portion 463pivotally connected to one of biases 434. In other embodiments, drum 26and its rotational axis 48 may be movably supported relative to drum 24in other fashions. For example, in lieu of being pivotably supported,drum 26 may alternatively be configured to translate or slide towardsand away from drum 24.

Biases 434 comprise mechanisms coupled between arms 432 and supports 428and configured to resiliently urge arms 432 in a counter-clock-wisedirection about axis 466 (as seen in FIG. 5) so as to also urge drum 26towards drum 24. Biases 434 assist in maintaining positioning of drum 26relative to drum 24 despite vibration or shock.

In the example illustrated, biases 434 comprise tension springsconnected between arms 432 and supports 428. In other embodiments,biases 434 may comprise a compression springs coupled between arms 432and a portion of one of supports 428 on an opposite side of axis 466. Instill other embodiment, biases 434 may comprise torsion springs coupledbetween supports 428 and arms 432 about axis 466. In some embodiments,biases 434 may be omitted such as where gravity is employed to urge drum26 towards drum 24.

Positioning system 222 comprises a system or arrangement of componentsor structures configured to adjust relative positioning and pressurebetween drum 24 and drum 26 and to maintain a selected relativepositioning and pressure despite run out or other dimensionalinconsistencies of drums 24, 26. Positioning system 422 includes bearers474A, 474B (collectively referred to as bears 474), bearers 476A, 476B(collectively referred to as bearers 476) and spacer mechanisms 478A,478B (collectively referred to as spacer mechanisms 478).

Bearers 474 and 476 are similar to bearers 74 and 76 described above.Bearers 474 comprises a cylindrical member, projection, hub or otherstructure coupled to drum 24 so as to rotate with drum 24 about axis 46.Bearers 474 include an outer circumferential surface 480 configured tobear against, abut, contact or engage portions of spacer mechanisms 478.

Bearer 476 is similar to bearer 474. Bearer 476 comprises a cylindricalmember, projection, hub or other structure coupled to drum 26 so as torotate with drum 26 about axis 48. Bearers 476 include an outercircumferential surface 482 configured to bear against, about, contactor engage portions of spacer mechanisms 478. Although bearers 474, 476are illustrated as having substantially the same diameter, and otherembodiment, bearers 474, 476 may have different diameters.

Spacer mechanisms 478 comprises one or more components between bearers474 and 476 in mutual engagement with surfaces 480 and 482 thatcontinuously extend a cross the gap or space between opposed portion ofsurfaces 480 and 482 so as to space bearers 474 and 476 from oneanother. Spacer mechanisms 478 maintain a selected spacing or distancebetween bearers 474, 476 to maintain a desire space or pressure betweendrums 24, 26. In addition, spacer mechanisms 478 are configured to beadjusted or actuated between different states in which opposed portionsof surfaces 480 and 482 of bearers 474 and 476 are differently spacedfrom one another. As a result, spacer mechanism 78 may be adjusted toselect a desired spacing or a desired compressive pressure between drums24 and 26.

According to one embodiment, each of spacer mechanisms 478 is adjustableor actuatable independent of the other spacer mechanism 478. As aresult, the left end of drums 24, 26 may be at a distinct spacing ordistinct pressure as compared to the right end of drums 24, 26. In yetanother embodiment, spacer mechanisms 478 are alternatively configuredto uniformly space bearers 474 and 476 at opposite ends of drums 24 and26 such that a uniform pressure or spacing exists actually across drums24 and 26.

In the example illustrated, each of spacer mechanisms 478 each includesspacer 481, support arm 482, spacer 485 and actuation system 493. Spacer481 comprises a cylindrical member or roller rotationally supported bysupport arm 482 about axis 497. Spacer 481 has an outer circumferentialsurface 495 in mutual contact with surfaces 480 of bearers 474 andspacer 485. In the example illustrated, spacer 481 rotates about agenerally fixed or stationary axis 497.

Support arm 482 comprises a rigid structure rotationally supportingspacer 481. In one embodiment, arms 482 extend from supports 428. Inother embodiment, arms 482 may extend from other structures. In aparticular example illustrated, arms 482 also support portions ofactuation system 493. In other embodiments, separate structures may beprovided for supporting actuation system 493.

Spacer 485 comprises a roller having an outer circumferential surface503 in mutual contact with surface 82 of spacer 76 and surface 395 ofspacer 381. In the example illustrated, spacer 303 is rotationallysupported about axis 505. In other embodiments, spacer 485 may comprisea cylinder having a low friction outer circumferential surface, thecylinder being fixed against rotation.

Actuation systems 493 comprise mechanisms operably coupled to spacer 485and configured to selectively move spacers 485 in either of thedirections indicated by arrows 507 relative to bearers 476 and spacers481. Such movement of spacers 485 adjusts the spacing between spacers481 and bearers 476. As a result, such movement of spacers 485 furtheradjusts the spacing between bearers 474 and 476 to cause adjustment ofthe relative positioning or compression pressures between drums 24 and26.

In the particular example illustrated, actuation system 493 includessupport arm 508, lever arm 510, rack gear 512, worm gear 514 and motor516. Support arm 508 comprises an arm or elongate structure rotationallysupporting spacer 45 about axis 505 and pivotally connected to lever arm510 about axis 518. Lever arm 512 comprises an angled arm pivotallyconnected to arm 508 about axis 518 and pivotally supported about axis520. In the particular example illustrated, lever arm 510 is pivotallysupported by support arm 482. In other embodiment, lever arm 512 may bepivotally supported about a fixed axis 520 by other stationarystructures. Pivoting of lever arm 510 results in movement of arm 508 andspacer 485 in one of the directions indicated by arrows 507.

Rack gear 510, worm gear 514 and motor 516 form an actuator configuredto selectively pivot lever arm 510 and move spacer 485. Rack gear 512comprises Iraqi or couple to lever arm 510. Worm gear 514 is in matchingengagement with rack gear 512 and is operably coupled to motor 516 so asto be rotationally driven by motor 516. Motor 516 comprises a rotaryactuator. In particular, motor 516 comprises a two directional motor,such as a stepper motor, configured to rotate worm gear 514 in eitherdirection so as to pivot lever arm 510 and move spacer 485.

In other embodiments, other actuators may alternatively be used to pivotlever arm 510. For example, a rack and pinion gear arrangement mayalternatively be employed. In still other embodiments, a hydraulic orpneumatic cylinder-piston assembly or an electric solenoid pivotallyconnected to lever arm 510 may be employed. In still other embodiment,lever arm 510 may be omitted where an actuator is provided that directlymoves spacer 485. For example, arm 508 May be directly connected to arack and pinion arrangement, a hydraulic or pneumatic cylinder-pistonassembly, an electric solenoid or a motor driven cam arrangement.

FIGS. 7 and 8 illustrate operation of positioning system 422. As shownby FIG. 7, in response to control signals received from controller 42,motor 516 of spacer mechanism 478A rotationally drives worm gear 514 topivot lever arm 510 so as to locate spacer 485 at a first position 525with respect to spacer 481 and bearer 476. As a result, the left end ofdrums 24, 26 (as seen in FIG. 6) has surfaces 50 and 54 spaced from oneanother by a distance S1. In a similar fashion, motor 516 of spacermechanism 478B (shown in FIG. 6) may similarly rotationally drive itsassociated worm gear 514 to pivot its associated lever arm 510 so as tolocate spacer 485 at a first position 525 with respect to spacer 481 andbearer 476. As a result, the right end of drums 24, 26 (as seen in FIG.6) also has surfaces 50 and 54 spaced from one another by a distance SI.Alternatively, the right end of drums 2426 may be spaced by a distinctdistance.

As shown in FIG. 8, in response to control signals received fromcontroller 42, motor 516 of spacer mechanism 478A rotationally drivesworm gear 514 to pivot lever arm 510 so as to locate spacer 485 at asecond position 527, distinct from the first position 525 (further tothe right as seen in FIG. 8), with respect to spacer 481 and bearer 476.As a result, the left end of drums 24, 26 (as seen in FIG. 6) hassurfaces 50 and 54 spaced from one another by a distance S2. In asimilar fashion, motor 516 of spacer mechanism 478B (shown in FIG. 6)may similarly rotationally drive its associated worm gear 514 to pivotits associated lever arm 510 so as to locate spacer 485 at a firstposition 527 with respect to spacer 481 and bearer 476. As a result, theright end of drums 24, 26 (as seen in FIG. 6) also has surfaces 50 and54 spaced from one another by a distance S2. Alternatively, the rightend of drums 2426 may be spaced by a distinct distance. As shown byFIGS. 7 and 8, the spacing between drums 24 and 26 may be set at any oneof a multitude of different spacings along a continuous spectrum orrange.

Although FIGS. 7 and 8 illustrate two distinct spacings S1 and S2 thatmay be established by positioning system 422, in other embodiments,positions 525 and 527 may both result in contact between surfaces 50 and54 of drums 24 and 26 or positions in which drums 24 and 26 imposeforces on one another across one or more intermediate structures ormediums between drums 24 and 26), respectively. However, at position525, distinct compressor forces may be exerted between drums 24, 26 ascompared to when spacer 45 is at position 527. Likewise, his orembodiments, distinct compressive pressures may be achieved across theaxial length of drums 24, 26 by varying the positions of spacer is atopposite ends of drums 24 and 26.

FIG. 9 schematically illustrates imaging system or printer 620 includingpositioning systems 422A, 422B (collectively referred to as positioningsystems 422) according to an example embodiment. Printer 620 comprises aliquid electrophotographic (LEP) printer. Printer 620, (sometimesembodied as part of an offset color press) includes drum 622 includingphotoconductor 624, charger 626, imager 628, ink carrier oil reservoir630, ink supply 631, developer 632, internally and/or externally heatedintermediate transfer member 634, impression member 638, cleaningstation 640, condenser 642, separator 144 and additive system 146. Drum622 comprises a movable support structure including photoconductor 624.Photoconductor 624, also sometimes referred to as a photoreceptor,comprises a multi-layered structure configured to be charged and to haveportions selectively discharged in response to optical radiation suchthat charged and discharged areas form a discharged image to whichcharged printing material is adhere. Drum 622 is configured to berotationally driven about axis 623 in a direction indicated by arrow 625by a motor and transmission (not shown). As a result, distinct surfaceportions of photoconductor 624 are transported between stations ofprinter 620 including charger 626, imager 628, ink developers 132,transfer member 634 and charger 634.

Charger 626 comprises a device configured to electrostatically chargesurface 647 of photoconductor 624. In one embodiment, charger 626comprises a charge roller which is rotationally driven while insufficient proximity to photoconductor 624 so as to transfer a negativestatic charge to surface 647 of photoconductor 624. In otherembodiments, charger 626 may alternatively comprise one or morecorotrons or scorotrons. In still other embodiments, other devices forelectrostatically charging surface 647 of photoconductor 624 may beemployed.

Imager 628 comprises a device configured to selectivelyelectrostatically discharge surface 647 so as to form an image. In theexample shown, imager 628 comprises a scanning laser which is movedacross surface 647 as drum 622 and its photoconductor 624 are rotatedabout axis 623. Those portions of surface 647 which are impinged bylight or laser 650 are electrostatically discharged to form an image (orlatent image) upon surface 647. In other embodiments, imager 628 mayalternatively comprise other devices configured to selectively emit orselectively allow light to impinge upon surface 647. For example, inother embodiments, imager 628 may alternatively include one or moreshutter devices which employ liquid crystal materials to selectivelyblock light and to selectively allow light to pass to surface 647. Inyet other embodiments, imager 628 may alternatively include shutterswhich include micro or nano light-blocking shutters which pivot, slideor otherwise physically move between a light blocking and lighttransmitting states.

Ink carrier reservoir 630 comprises a container or chamber configured tohold ink carrier oil for use by one or more components of printer 620.In the example illustrated, ink carrier reservoir 630 is configured tohold ink carrier oil for use by cleaning station 640 and ink supply 631.In one embodiment, as indicated by arrow 651, ink carrier reservoir 630serves as a cleaning station reservoir by supplying ink carrier oil tocleaning station 640 which applies the ink carrier oil againstphotoconductor 624 to clean the photoconductor 624. In one embodiment,cleaning station 640 further cools the ink carrier oil and applies inkcarrier oil to photoconductor 624 to cool surface 647 of photoconductor624. For example, in one embodiment, cleaning station 640 may include aheat exchanger or cooling coils in ink care reservoir 630 to cool theink carrier oil. In one embodiment, the ink carrier oil supply tocleaning station 640 further assists in diluting concentrations of othermaterials such as particles recovered from photoconductor 624 duringcleaning.

After ink carrier oil has been applied to surface 647 to clean and/orcool surface 647, the surface 647 is wiped with an absorbent rollerand/or scraper. The removed carrier oil is returned to ink carrierreservoir 130 as indicated by arrow 653. In one embodiment, the inkcarrier oil returning to ink carrier reservoir 630 may pass through oneor more filters 657 (schematically illustrated). As indicated by arrow655, ink carrier oil in reservoir 630 is further supplied to ink supply631. In other embodiments, ink carrier reservoir 630 may alternativelyoperate independently of cleaning station 640, wherein ink carrierreservoir 630 just supplies ink carrier oil to ink supply 631.

Ink supply 631 comprises a source of printing material for inkdevelopers 632. Ink supply 631 receives ink carrier oil from carrierreservoir 630. As noted above, the ink carrier oil supplied by inkcarrier reservoir 630 may comprise new ink carrier oil supplied by auser, recycled ink carrier oil or a mixture of new and recycling carrieroil. Ink supply 631 mixes being carrier oil received from ink carereservoir 630 with pigments or other colorant particles. The mixture isapplied to ink developers 632 as needed by ink developers 632 using oneor more sensors and solenoid actuated valves (not shown).

In the particular example shown, the raw, virgin or unused printingmaterial may comprise a liquid or fluid ink comprising a liquid carrierand colorant particles. The colorant particles have a size of less than2μ. In different embodiments, the particle sizes may be different. Inthe example illustrated, the printing material generally includesapproximately 3% by weight, colorant particles or solids part to beingapplied to surface 147. In one embodiment, the colorant particlesinclude a toner binder resin comprising hot melt adhesive.

In one embodiment, the liquid carrier comprises an ink carrier oil, suchas Isopar, and one or more additional components such as a highmolecular weight oil, such as mineral oil, a lubricating oil and adefoamer. In one embodiment, the printing material, including the liquidcarrier and the colorant particles, comprises HEWLETT-PACKARD ELECTROINK commercially available from Hewlett-Packard.

Ink developers 632 comprises devices configured to apply printingmaterial to surface 647 based upon the electrostatic charge upon surface647 and to develop the image upon surface 647. According to oneembodiment, ink developers 632 comprise binary ink developers (BIDs)(commercially available from Hewlett-Packard) circumferentially locatedabout drum 622 and photoconductor 624. Such ink developers areconfigured to form a substantially uniform 6μ thick electrostaticallycharged film composed of approximately 20% solids which is transferredto surface 647. In yet other embodiments, ink developers 632 maycomprise other devices configured to transfer electrostatically chargedliquid printing material or toner to surface 647. In still otherembodiments, developers 632 may be configured to apply a dryelectrostatically charged printing material, such as dry toner, tosurface 147.

Intermediate transfer member 634 comprises a drum configured to transferthe printing material upon surface 647 to a print medium 652(schematically shown). Intermediate transfer member 634 includes anexterior surface 654 which is resiliently compressible and which is alsoconfigured to be electrostatically charged. Because surface 654 isresiliently compressible, surface 654 conforms and adapts toirregularities in print medium 652. Because surface 654 is configured tobe electrostatically charged, surface 654 may be charged so as tofacilitate transfer of printing material from surface 647 to surface654. In one embodiment, intermediate transfer member 634 may include aan external blanket 658. Blanket 658 which provides intermediatetransfer member 634 with surface 654.

Heating system 636 comprises one or more devices configured to applyheat to printing material being carried by surface 654 fromphotoconductor 624 to medium 652. In the example illustrated, heatingsystem 636 includes internal heater 660, external heater 662 and vaporcollection plenum 663. Internal heater 660 comprises a heating devicelocated within drum 656 that is configured to emit heat or inductivelygenerate heat which is transmitted to surface 654 to heat and dry theprinting material carried at surface 654. External heater 662 comprisesone or more heating units located about transfer member 634. Accordingto one embodiment, heaters 660 and 662 may comprise infrared heaters.

Heaters 660 and 662 are configured to heat printing material to atemperature of at least 85° C. and less than or equal to about 110° C.In still other embodiments, heaters 660 and 662 may have otherconfigurations and may heat printing material upon transfer member 634to other temperatures. In particular embodiments, heating system 636 mayalternatively include one of either internal heater 660 or externalheater 662.

Vapor collection plenum 663 comprises a housing, chamber, duct, vent,plenum or other structure at least partially circumscribing intermediatetransfer member 634 so as to collect or direct ink or printing materialvapors resulting from the heating of the printing material on transfermember 634 for discharge or to a condenser (not shown) or discharge orrecycling.

Impression member 638 comprises a cylinder adjacent to intermediatetransfer member 634 so as to form a nip 664 between member 634 andmember 638. Medium 652 is generally fed between transfer member 634 andimpression member 638, wherein the printing material is transferred fromtransfer member 634 to medium 652 at nip 664.

Cleaning station 640 comprises one or more devices configured to removeany residual printing material from photoconductor 624 prior to surfaceareas of photoconductor 624 being once again charged at charger 626. Inone embodiment, cleaning station 640 may comprise one or more devicesconfigured to apply a cleaning fluid to surface 647, wherein residualtoner particles are removed by one or more is absorbent rollers. In oneembodiment, cleaning station 640 may additionally include one or morescraper blades. In yet other embodiments, other devices may be utilizedto remove residual toner and electrostatic charge from surface 647.

In operation, heating system 636 applies heat to such printing materialupon surface 654 so as to evaporate the carrier liquid of the printingmaterial and to melt toner binder resin of the color and particles orsolids of the printing material to form a hot melt adhesive. Thereafter,the layer of hot colorant particles forming an image upon surface 654 istransferred to medium 652 passing between transfer member 634 andimpression member 638. In the embodiment shown, the hot colorantparticles are transferred to print medium 652 at approximately 90° C.The layer of hot colorant particles cool upon contacting medium 652 oncontact in nip 664.

These operations are repeated for the various colors or preparation ofthe final image to be produced upon medium 652. In other embodiments, inlieu of creating one color separation at a time on a surface 654,sometimes referred to as “multi-shot” process, the above process may bemodified to employ a one-shot color process in which all colorseparations are layered upon surface 654 of intermediate transfer member634 prior to being transferred to and deposited upon medium 652.

In printer 620, positioning systems 422A is employed to control orregulate the spacing between drum 622 and intermediate transfer member634. Positioning system 422B is employed to control or regulate thespacing or compressive pressure between intermediate transfer member 634and impression member 138. In other embodiments, printer 620 mayalternatively omit one of positioning systems 422.

According to one embodiment, drum 122 is pivotally supported relative tosupports 428 (shown in FIG. 6) by arms 432 (shown in FIG. 6) while beingresiliently biased towards intermediate transfer member 634 by biases434 (shown in FIG. 6). In operation, controlled movement of spacer 485(shown in FIG. 5) adjusts relative positioning and drum 622 andintermediate transfer member 634.

According to one embodiment, the drum of impression member 138 ispivotally supported by supports, such as supports 428 (shown in FIG. 6)while being resiliently biased towards intermediate transfer member 634by biases 434 (shown in FIG. 6). In operation, controlled movement ofspacer 485 (shown in FIG. 5) adjusts relative positioning of member 638and intermediate transfer member 634.

In yet another embodiment, drum 622 is pivotally supported relative tosupports 428 (shown in FIG. 6) by arms 432 (shown in FIG. 6) while beingresiliently biased towards intermediate transfer member 634 by biases434 (shown in FIG. 6). In operation, controlled movement of spacer 485(shown in FIG. 5) adjusts relative positioning and drum 122 andintermediate transfer member 634. At the same time, the intermediatetransfer member 638 is pivotally supported by supports, such as supports428 (shown in FIG. 6) while being resiliently biased towards impressionmember 638 by biases 434 (shown in FIG. 6). In operation, controlledmovement of spacer 485 (shown in FIG. 5) adjusts relative positioning ofmember 638 and intermediate transfer member 634.

Although the present disclosure has been described with reference toexample embodiments, workers skilled in the art will recognize thatchanges may be made in form and detail without departing from the spiritand scope of the claimed subject matter. For example, although differentexample embodiments may have been described as including one or morefeatures providing one or more benefits, it is contemplated that thedescribed features may be interchanged with one another or alternativelybe combined with one another in the described example embodiments or inother alternative embodiments. Because the technology of the presentdisclosure is relatively complex, not all changes in the technology areforeseeable. The present disclosure described with reference to theexample embodiments and set forth in the following claims is manifestlyintended to be as broad as possible. For example, unless specificallyotherwise noted, the claims reciting a single particular element alsoencompass a plurality of such particular elements.

1. An apparatus comprising: a first drum; a second drum; and apositioning system configured to adjust relative positioning andpressure between the first drum and the second drum and to maintain aselected relative positioning and pressure despite run out of either ofthe first drum or the second drum.
 2. The apparatus of claim 1, whereinthe positioning system includes a powered actuator to adjust thepositioning and pressure.
 3. The apparatus of claim 1, wherein thepositioning system comprises: a first bearer coupled to the first drumso as to rotate with the first drum, the first bearer having a firstdiameter less than a diameter of the first drum; a second bearer coupledto the second drum so as to rotate with a second drum, the second bearerhaving a second diameter less than a diameter of the second drum; and afirst spacer mechanism in engagement with the first bearer and thesecond bearer, the spacer mechanism being actuatable between a firststate in which the first bearer and a second bearer spaced by the spacermechanism a first distance and a second state in which the first bearerand the second bearer are spaced by the spacer mechanism a seconddistance different than the first distance.
 4. The apparatus of claim 3,wherein the first spacer mechanism is proximate a first axial end of thefirst drum and wherein the apparatus further comprises a second spacermechanism in engagement with the first bearer and the second bearerproximate a second axial and of the first drum, the second spacermechanism being actuatable between a first state in which the firstbearer and a second bearer spaced by the second spacer mechanism a thirddistance and a second state in which the first bearer and the secondbearer are spaced by the second spacer mechanism a fourth distancedifferent than the third distance.
 5. The apparatus of claim 4, whereinthe first spacer mechanism and the second spacer mechanism areindependently adjustable and configured such that the first spacermechanism spaces the first bearer and the second bearer by a firstspacing at the first axial end of the first drum and such that thesecond spacer mechanism spaces the first bearer and the second bearer bya second spacing at the second axial end of the first drum.
 6. Theapparatus of claim 4, wherein the first bearer is pivotally supportedrelative to the second bearer.
 7. The apparatus of claim 6, wherein thefirst bearer is resiliently biased towards the second bearer.
 8. Theapparatus of claim 1, wherein the positioning system comprises: a firstbearer associated with the first drum; a second bearer associated withthe second drum; a first roller in contact with the first bearer; and asecond roller in contact with the first bearer and the first roller,wherein the second roller rotates about a first axis that is configuredto be adjustably positioned with respect to the first roller and thefirst bearer.
 9. The apparatus of claim 8 further comprising anactuation system for moving the first axis of the second roller.
 10. Theapparatus of claim 9, wherein the actuation system comprises: a firstarm rotatably supporting the second roller; a second arm configured topivot about a second axis and pivotally connected to the first arm abouta third axis; and an actuator for selectively pivoting the second arm.11. The apparatus of claim 10, wherein the actuator comprises: a rackgear associated with the second arm; a worm gear in engagement with therack gear; and a motor operably coupled to the worm gear.
 12. Theapparatus of claim 8, wherein the first bearer and the second bearer ofa fully round outer circumferential surface.
 13. The apparatus of claim1 further comprising a developer configured to transfer toner onto oneof the first drum and the second drum.
 14. The apparatus of claim 1,wherein the first drum and the second drum are configured to receivetheir between a medium to be printed upon.
 15. The apparatus of claim 1,wherein at least one of the first drum and the second drum includesnon-round outer surface portions.
 16. The apparatus of claim 1, whereinat least one of the first drum and the second drum has a compressibleouter surface.
 17. The apparatus of claim 1, wherein the positioningsystem is configured to maintain a spacing greater than zero betweenouter surfaces of the first drum and the second drum.
 18. A methodcomprising: adjusting relative positioning and pressure between a firstdrum and a second drum; and maintaining a selected relative positioningand pressure between the first drum and the second drum despite run outof either of the first drum or the second drum.
 19. The method of claim18, wherein the adjusting comprises changing a spacer mechanism inmutual engagement with a first bearer, associated with a first drum andhaving a first diameter less than a diameter of the first drum, and asecond bearer, associated with a second drum and having a seconddiameter less than a diameter of the second drum.
 20. An apparatuscomprising: a first drum; a second drum; a first bearer coupled to thefirst drum so as to rotate with the first drum, the first bearer havinga first diameter less than a diameter of the first drum; a second bearercoupled to the second drum so as to rotate with a second drum, thesecond bearer having a second diameter less than a diameter of thesecond drum; and a first spacer mechanism in engagement with the firstbearer and the second bearer, the spacer mechanism being actuatablebetween a first state in which the first bearer and a second bearerspaced by the spacer mechanism a first distance and a second state inwhich the first bearer and the second bearer are spaced by the spacermechanism a second distance different than the first distance.